Data Sheet

AD5624/AD5664

Rev. A | Page 13 of 23

TERMINOLOGY

Relative Accuracy or Integral Nonlinearity (INL)

For the DAC, relative accuracy or integral nonlinearity is a

measurement of the maximum deviation, in LSBs, from a straight

line passing through the endpoints of the DAC transfer function. A

typical INL vs. code plot can be seen in Figure 5 and Figure 6.

Differential Nonlinearity (DNL)

Differential nonlinearity is the difference between the measured

change and the ideal 1 LSB change between any two adjacent

codes. A specified differential nonlinearity of ±1 LSB maximum

ensures monotonicity. This DAC is guaranteed monotonic by

design. A typical DNL vs. code plot can be seen in Figure 7 and

Figure 8.

Zero-Scale Error

Zero-scale error is a measurement of the output error when

zero code (0x0000) is loaded to the DAC register. Ideally, the

output is 0 V. The zero code error is always positive in the

AD5624/AD5664 because the output of the DAC cannot go

below 0 V. It is due to a combination of the offset errors in the

DAC and the output amplifier. Zero code error is expressed in

mV. A plot of zero code error vs. temperature can be seen in

Figure 13.

Full-Scale Error

Full-scale error is a measurement of the output error when full-

scale code (0xFFFF) is loaded to the DAC register. Ideally, the

A plot of full-scale error vs. temperature can be seen in Figure 12.

Gain Error

This is a measure of the span error of the DAC. It is the deviation in

slope of the DAC transfer characteristic from ideal expressed as

a % of FSR.

Zero Code Error Drift

This is a measurement of the change in zero code error with a

change in temperature. It is expressed in μV/°C.

Gain Temperature Coefficient

This is a measurement of the change in gain error with changes

in temperature. It is expressed in ppm of FSR/°C.

Offset Error

transfer function. Offset error is measured on the AD5624/

AD5664 with code 512 loaded in the DAC register. It can be

negative or positive.

DC Power Supply Rejection Ratio (PSRR)

This indicates how the output of the DAC is affected by changes

Output Voltage Settling Time

This is the amount of time it takes for the output of a DAC to

settle to a specified level for a ¼ to ¾ full-scale input change and is

Digital-to-Analog Glitch Impulse

Digital-to-analog glitch impulse is the impulse injected into the

analog output when the input code in the DAC register changes

state. It is normally specified as the area of the glitch in nV-s,

and is measured when the digital input code is changed by 1 LSB at

the major carry transition (0x7FFF to 0x8000) as shown in

Figure 23.

Digital Feedthrough

Digital feedthrough is a measure of the impulse injected into

the analog output of the DAC from the digital inputs of the

DAC, but is measured when the DAC output is not updated. It

is specified in nV-s, and measured with a full-scale code change

on the data bus, that is, from all 0s to all 1s and vice versa.

Total Harmonic Distortion (THD)

This is the difference between an ideal sine wave and its attenuated

version using the DAC. The sine wave is used as the reference

for the DAC, and the THD is a measurement of the harmonics

present on the DAC output. It is measured in dB.

Noise Spectral Density

This is a measurement of the internally generated random noise.

Random noise is characterized as a spectral density (nV/√Hz).

It is measured by loading the DAC to midscale and measuring

noise at the output. It is measured in nV/√Hz. A plot of noise

spectral density can be seen in Figure 28.

DC Crosstalk

DC crosstalk is the dc change in the output level of one DAC in

response to a change in the output of another DAC. It is measured

with a full-scale output change on one DAC (or soft power-down

and power-up) while monitoring another DAC kept at midscale.

It is expressed in μV.

DC crosstalk due to load current change is a measure of the

impact that a change in load current on one DAC has to another

DAC kept at midscale. It is expressed in μV/mA.